Strains of bacteria and pharmaceutical composition containing one or more of such strains and use of same for preventing and treating diseases associated with or caused by altered metabolism of bile acids

ABSTRACT

Strains of bacteria characterized by exhibiting: (a) a 7α-dehydroxylase activity of less than 50%, and (b) a bile acid deconjugation activity of less than 50%, and descendants, mutants and derivatives thereof preserving activities (a) and (b); and a pharmaceutical composition using one or more of such strains and use of same for preventing and treating diseases associated with or caused by an altered metabolism of bile acids.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.09/796,432, filed Mar. 2, 2001, which is a division of U.S. patentapplication Ser. No. 08/813,776, filed Mar. 7, 1997, which claimspriority to Italian Patent Application No. MI96A000468, filed Mar. 11,1996. The entire contents of each of the above are incorporated hereinby reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to strains of bacteria and pharmaceuticalcompositions containing one or more of such strains and the use of samefor preventing and treating diseases associated with or caused by analtered metabolism of bile acids.

2. Discussion of the Background

Hepatic bile is a pigmented isotonic fluid with an electrolytecomposition resembling blood plasma. Major components of bile includewater (82 percent), bile acids (12 percent), lecithin and otherphospholipids (4 percent), and unesterified cholesterol (0.7 percent).Other constituents include conjugated bilirubin, proteins, electrolytes,mucus and the final products of hepatic transformation of drugs,hormones, etc. The liver production of bile, in basal conditions, isapproximately 500-1000 ml/day.

The primary bile acids, cholic acid (CA) and chenodeoxycholic acid(CDCA), are synthesized from cholesterol in the liver, conjugated withglycine or taurine, and excreted into the bile. Secondary bile acids,including deoxycholic acid (DCA) and lithocholic acid (LA), are formedin the colon as bacterial metabolites of the primary bile acids. Otherbile acids, called tertiary bile acids (e.g.: ursodeoxycholicacid—UDCA), are formed in the gut following the enzymatic epimerizationof —OH groups on sterol rings by the intestinal flora.

In normal bile, the ratio of glycine to taurine conjugates is about 2:1,while in patients with cholestasis, increased concentrations of sulfateand glucuronide conjugate of bile acids are often found. The intestinalmicroflora transforms the bile acids into different metabolites. Thesebiotransformations include the hydrolysis of the bond between the bileacid and taurine or glycine, with formation of unconjugated or free bileacids and taurine or glycine. The unconjugated bile acids are thereforemade available for the oxidation of the hydroxylic groups in positionsC3, C7, and C12 and for the dehydroxylation in positions 7α and 7β. Thislatter transformation leads to the formation of the secondary bile acidsDCA and LA. The primary bile acids, deconjugated bile not transformed,and the secondary biliary acids are reabsorbed from the gut lumen andenter the portal bloodstream, then are taken up by hepatocytes,conjugated with glycine or taurine and resecreted into the bile(enterohepatic circulation).

Normally, the bile acid pool circulates approximately 5 to 10 timesdaily. Intestinal absorption of the pool is about 95% efficient, sofecal loss of bile acids is in the range of 0.3 to 0.6 g/day. The fecalloss is compensated by an equal daily synthesis.

For this reason the composition of the pool of biliary acids present inthe bile is the result of complex interactions occurring between theliver and the microflora enzymes.

Deconjugation activity is a characteristic shared by many bacteria,aerobes and anaerobes, but is particularly common among the obligateanaerobic bacteria, i.e. Bacteroides, Eubacteria, Clostridia,Bifidobacteria, etc. The majority of the bacteria is active against bothglycine and taurine conjugates; however, some of them have a certaindegree of specificity, depending on the bound amino acid and the numberof hydroxides bound to the steroid nucleus. The free biliary acidsobtained following the action of the bacterial hydrolases can undergothe oxidation of the hydroxide groups present at the C3, C7, and C12positions by the hydroxysteroidodehydrogenase.

The interest in the metabolic disorders of biliary acids comes from thehypothesis that biliary acids and/or metabolites thereof are involved inthe pathogenesis of some hepato-biliary and gastroenterologic diseases:biliary dyspepsia, cholelithiasis, acute and chronic hepatopathies,inflammatory diseases of the colon, etc.

Very often in literature the hydrophobicity of the bile acid iscorrelated with detergency; the secondary bile acids are morehydrophobic than the primary bile acids, the deoxycholic acid (DCA)being actually more detergent than the cholic acid (CA). Therefore anincreased concentration of DCA in the bile may involve: a) anaugmentation of the secretion of cholesterol, with increased saturationindex; b) a cytotoxic effect on the liver cells.

For this reason a qualitative modification of the bile acids patterncould be a decisive factor, especially in treating the above-mentionedpathologies.

Thus, there remains a need for effective bacterial strains orcompositions that, by reducing the 7α-dehydroxylase activity and at thesame time deconjugation, can be used for treating and/or preventingdiseases associated with metabolic disorders of the biliary acids.

No bacteria strains have been found that are capable of qualitativelymodifying the bile acid pattern in such a way.

SUMMARY OF THE INVENTION

Accordingly, it is one object of the present invention to provide novelstrains of bacteria, in particular gram-positive bacteria, which areuseful for treating and/or preventing diseases associated with or causedby a metabolic disorder of biliary acids.

It is another object of the present invention to provide pharmaceuticalcompositions which contain one or more strains of such bacteria and areuseful for treating and/or preventing diseases associated with or causedby a metabolic disorder of biliary acids.

It is another object of the present invention to provide a novel methodfor treating and/or preventing diseases associated with or caused by ametabolic disorder of biliary acids.

The foregoing and other objects, which will become more apparent duringthe following detailed description, have been achieved by the inventors,who have found bacteria strains having a reduced or zero7α-dehydroxylase activity and a reduced or zero ability to deconjugatebile acids. This is in contrast with the previous known art.Accordingly, the present invention provides the use of such strains tomodify the bile acid metabolism in a useful manner to prevent or treatdiseases caused by or associated with metabolic disorders of biliaryacids.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Thus, in a first embodiment, the present invention provides novelstrains of bacteria which have a 7α-dehydroxylase activity of less than50%, preferably less than 25%, and a conjugated bile acid deconjugationactivity of less than 50%, preferably less than 25%.

The essential features of the strains according to the present inventionare defined in claim 1; specific strains having said features aredefined in the dependent claims 2 to 11.

The present invention also provides a pharmaceutical composition fortreating and/or preventing diseases associated with or caused by analtered metabolism of biliary acids, said composition comprising atleast one bacteria strain according to the present invention. Theessential features of the composition according to the present inventionare defined in claim 12; specific embodiments of said composition aredefined in the dependent claims 13 to 25.

In another embodiment, the present invention provides a method fortreating and/or preventing diseases caused by or associated with analtered metabolism of biliary acids by administering to a patient inneed thereof one or more strains of bacteria which have a7α-dehydroxylase activity of less than 50%, preferably less than 25%,and a conjugated bile acid deconjugation activity of less than 50%,preferably less than 25%, or a pharmaceutical composition containing oneor more such strains of bacteria.

The essential features of said method are defined in claim 26; specificembodiments are defined in the dependent claims 27 to 36.

In the context of the present invention, the diseases associated with orcaused by a metabolic disorder of the biliary acids include liverdiseases and diseases of the digestive apparatus, such as blind loopsyndrome, biliary gallstones, cirrhosis, chronic hepatopathies, acutehepatopathies, cystic fibrosis, intrahepatic cholestasis, intestinalinflammatory diseases, colonpathies, malabsorption. The presentpharmaceutical compositions may also be used to prevent the onset ofbiliary gallstones in women during pregnancy or subsequent periods andin subjects undergoing weight-loss programs or diets.

The 7α-dehydroxylase activity of the bacteria strain should be less then50%, preferably less than 25%. The 7α-dehydroxylase activity values arethose measured by theαmethod described in Example 1 below. Specifically,the 10⁷ cells of the strain in question are incubated at 37° C. for 48hours, in 15 ml of the specific culture medium with the addition of 2mg/ml of glycocholic acid (GCA) or 2 mg/ml of taurocholic acid (TCA),and then the amount of 7α-dehydroxylated product is measured. Thepercentage value for the 7α-dehydroxylase activity is calculated by thefollowing formula:

7α-dehydroxylase activity=[(mass of 7α-dehydroxylated product after 48hours of incubation)/(mass of GCA or TCA at the start ofincubation)]×100.

The 7α-dehydroxylase activity for any given strain is the higher of thenumbers measured for GCA and TCA.

Based on the above, the bacteria strain to be administered should inaddition have a conjugated bile acid deconjugation activity of less than50%, preferably less than 25%. The ability to deconjugate bile acid isdetermined by using the same incubation procedure described formeasuring the 7α-dehydroxylase activity followed by measuring the amountof deconjugated product formed. The deconjugation activity is calculatedusing the following formula:

Deconjugation activity=[(mass of GCA or TCA at the after 48 hours ofincubation)/(mass of GCA or TCA at the start of incubation)]×100.

The deconjugation activity for any given strain is the higher of thenumbers measured for GCA and TCA.

The bacteria strains of the present invention may be administeredenterically. Preferably, the bacteria strains of the present inventionare administered orally.

Although a single bacteria strain may be administered, it is alsopossible to administer a mixture of two or more bacteria according tothe present invention.

Although the exact dosage of bacteria to be administered will vary withthe condition and size of the patient, the exact disease being treated,and the identity of the strains being administered, good results havebeen achieved by administering 10³ to 10¹³ cells of the bacteria/g,preferably 10⁸ to 10¹² of the bacteria strain/g. To achieve the goodeffects of the present invention, it is preferred that the strain beadministered in an amount and a concentration sufficient to result inthe intestines of the patient being populated with an important amountthereof. Thus, it is preferred that the strain be administered in acomposition which contains 10³ to 10¹³ cells of the strain/g, preferably10⁸ to 10¹² cells of the strain/g and that the composition beadministered in such a regimen so that the patient receives 100 mg to100 g of the strain/day, preferably 1 g to 20 g of the strain/day, for aperiod of 1 to 365 days, preferably 3 to 60 days in case of therapy, oraccording to periodical cycles in case of prophylaxis. The bacteriastrain may be administered in any form suitable for enteraladministration, such as capsules, tablets, or liquids for oraladministration or liquids for enteral administration.

Typically, the administration of the bacteria strain according to thepresent invention can be prescribed after the diagnosis of metabolicdisorders of the biliary acids. However, in the case of the prophylaxisof biliary gallstones, the strain may be administered when the subjectis determined to belong to an at-risk population, such as becomingpregnant or beginning a weight-loss program or diet. In addition, thepresent strain of bacteria may be administered after a patient has hadtheir gallbladder removed.

In a preferred embodiment, the coadministration of lactulose is providedwhen the disease being treated is cirrhosis. Suitably, the lactulose isadministered in an amount of 100 mg to 100 g/day, preferably 1 g to 20g/day.

In another preferred embodiment, the coadministration of bile acid-basedpreparations, such as ursodeoxycholic acid or tauroursodeoxycholic acid,is provided. Suitably, the ursodeoxycholic or tauroursodeoxycholic acidis 7; administered in an amount of 10 to 3,000 mg/day, preferably 50 to800 mg/day.

The present invention finally provides novel pharmaceutical compositionsfor treating and/or preventing the metabolic disorders of the biliaryacids which comprise (a) one or more strains of bacteria having a7α-dehydroxylase activity of less than 50%, preferably less than 25%,and a bile acid deconjugation activity of less than 50%, preferably lessthan 25%, and (b) a pharmaceutically acceptable carrier. Preferably, thepresent pharmaceutical compositions contain the strain(s) of bacteria ina concentration of 10³ to 10′³ cells/g, preferably 10⁸ to 10¹² cells/g.The pharmaceutically acceptable carrier may be any which is suitable forenteral administration and is compatible with the strain of bacteria,such as dextrose, calcium carbonate together with different additionalsubstances such as starch, gelatin, vitamins, antioxidants, stains ortaste-improving substances.

As an optional component, the compositions of the invention may possiblycontain a drug compatible with the bacteria employed and capable ofpotentiating the activity of the active ingredients present.Anticholinergic drugs, antihistamines, adrenergic, antiulcer, antiacid,antidiarroic, and anti-inflammatory drugs, sedatives, antipyretis,choleretics antirheumatic agents, analgesic drugs, diuretics, antisepticagents, antilipemic hepatoprotective drugs and drugs active on thegastrointestinal motility (e.g., trimebutine) may be herein mentioned.

When treating cirrhosis, it is preferred that the pharmaceuticalcomposition further comprise lactulose. Suitably, the composition willcontain sufficient lactulose to result in the administration of 100 mgto 100 g/day, preferably 1 g to 20 g/day of lactulose. When treatingbiliary cirrhosis and chronic hepatitis, it is preferred that thepharmaceutical composition comprise bile acid-based preparations, suchas ursodeoxycholic acid or tauroursodeoxycholic acid. Suitably, thecomposition will contain sufficient bile acid preparation to result inthe administration of 10 to 3,000 mg/day of such bile acid preparations,preferably 50 to 800 mg/day of ursodeoxycholic acid ortauroursodeoxycholic acid.

Other features of the invention will become apparent in the course ofthe following descriptions of exemplary embodiments which are given forillustration of the invention and are not intended to be limitingthereof.

EXAMPLES Example 1

Strains of the following species have been tested: Streptococcusthermophilus, Streptococcus faecium, Lactobacillus acidophilus,Lactobacillus bulgaricus, Lactobacillus plantarum, Bifidobacteriuminfantis. Each strain (10⁷ CFU) was cultivated in duplicate in specificnutrient broths (15 ml); “CFU” means “colony forming units”.

List of the employed culture media depending on the different speciesBifidobacterium infantis MRS + 0.5% glucose (added after sterilizationby diluting a 20% sterile solution) Streptococcus thermophilus M17 Allthe remaining strains MRS Composition of the MRS broth g/liter universalpeptone 10.0 g meat extract 5.0 g yeast extract 5.0 g D (+)-glucose 20.0g potassium hydrogen phosphate 2.0 g Tween 80 1.0 g dibasic ammoniumcitrate 2.0 g sodium acetate 5.0 g magnesium sulfate 0.1 g manganoussulfate 0.05 g Preparation: dissolve 50 g/l in distilled water,sterilized at 121° C. for 15 minutes - pH 6.5 ± 0.1 at 25° C.Composition M17 broth (Merck): g/liter soybean flour peptone 5.0 g meatpeptone 2.5 g casein peptone 2.5 g yeast extract 2.5 g meat extract 5.0g D (+)-lactose 5.0 g ascorbic acid 0.5 g sodium-β-glycerophosphate 19.0g magnesium phosphate 0.25 g

Preparation: dissolve 42.5 g/l in distilled water, sterilized at 121° C.for 15 minutes—pH 7.2±0.1 at 25°.

Bifidobacterium infantis was cultivated under anaerobic conditions sinceit is known that it is an anaerobic bacterium. After 24 hours ofincubation at 37° C. to each tube was added an amount of bile saltequivalent to 30 mg in order to obtain a final concentration of 2 mg/ml.The bile acids employed are: glycocholic acid (GCA) and taurocholic acid(TCA), obtained from Sigma Chemicals. Each bile acid was addedseparately to each series of bacterial cultures.

After 48 hours of incubation, isopropanol, 3 ml, was added for 2minutes. Then it was centrifuged at 400 rpm for 15 minutes and thesupernatant was collected (5 ml). The supernatant was kept refrigeratedat −30° C. until it was analyzed. The percentage of conjugated bile saltpresent was determined by HPLC (high performance liquid chromatography)utilizing a Gilson apparatus equipped with a detector Diode array mod1000 and a Spherisorb 5 μm ODS 2 C18 reverse phase column, a mobilephase composed by methanol/buffered phosphate (20 mMol), pH 2.5 inwater/acetonitrile/water (150:60:20:20 by volume), a fluid speed of 0.85ml/min, at a wavelength of 205 nm; 100 μl of the sample to be tested,dried under nitrogen, were extracted with 100 μl of the mobile phasecontaining as an internal standard 7α-OH-12α-OH-dihydroxy-58-cholanicacid (Calbiochem U.S.A.) at a concentration of 2 mg/ml.

The recovery percentage of the bile acid incubated with the bacterialcultures was calculated by the ratio of the area of the bile acid to bedetected (GCA or TCA) to the area of the internal standard. When thequantity of the conjugated bile acid found in the bacterial culturesafter 48 hours of incubation was less than 50%, thin layerchromatography (TLC) was performed on silica 60 gel plates to detect thepresence of CA and DCA, using a mobile phase ofcyclohexane/isopropanol/acetic acid (30:10:1 by volume). On every plate,20 μl of the alcoholic extract of the sample, 20 μl of a solution of CAand DCA, and 20 μl of CA, 20 μl of DCA, were spotted. The plates afterdevelopment at room temperature, were treated with sulfuric acid andwarmed at 145° C. until the appearance of the colored spots.

The results of the deconjugation experiments (Table I) show that 5 outof the 16 strains tested with GCA were able to completely deconjugatethe bile acid added to the culture, as previously reported in theliterature and widely known to all researchers. Surprisingly, tenstrains were able to deconjugate GCA but not completely, ranging from 9to 90 percent (Table I). There was no difference among aerobic andanaerobic bacteria. Two strains, Streptococcus thermophilus YS 52 andBifidobacterium infantis Bi 6 do not have any deconjugating activity forGCA. The strain YS 52 in addition does not attack the bile acid—taurinebond.

Only one out of the 16 strains tested was able to totally deconjugatethe TCA: the Bifidobacterium infantis Bi 6.

The results of the dehydroxylation experiments (Table II) show that onlyone (Bi 4) out of the 16 strains is able to completely dehydroxylateGCA. Six strains did not dehydroxylate at all: YS 52; SF 2; SF 4; LA 3;LA 10; and .* Bi 6. The other strains were able to dehydroxylate GCA butnot completely, ranging from 9% to 90%. As to TCA, seven strains do notdehydroxylate it at all: YS 52; SF 3; LA 3; LA 10; LB 1; LB 7; and LB77. One strain, Bi 6, dehydroxylated TCA completely; the other strainsdehydroxylated TCA according to varying percentages.

TABLE I Percentage of deconjugation of GCA and TCA by bacterial culturesafter 48 hours of incubation ACCESSION BACTERIUM NO. GCA % TCA %Streptococcus thermophilus YS 46 I-1668 9 9 Streptococcus thermophilusYS 48 I-1669 17 11 Streptococcus thermophilus YS 52 I-1670 0 0Streptococcus faecium SF 2 100 3 Streptococcus faecium SF 3 I-1671 27 0Streptococcus faecium SF 4 100 12 Lactobacillus acidophilus LA 3 100 80Lactobacillus acidophilus LA 10 100 95 Lactobacillus bulgaricus LB 1I-1664 9 0 Lactobacillus bulgaricus LB 3 I-1665 20 12 Lactobacillusbulgaricus LB 7 I-1666 14 0 Lactobacillus bulgaricus LB 77 I-1667 20 0Bifidobacterium infantis Bi 2 80 15 Bifidobacterium infantis Bi 3 90 10Bifidobacterium infantis Bi 4 100 26 Bifidobacterium infantis Bi 6 0 100

TABLE II Percentage of dehydroxylation of GCA and TCA by bacterialcultures after 48 hours of incubation ACCESSION BACTERIUM NO. GCA % TCA% Streptococcus thermophilus YS 46 I-1668 9 9 Streptococcus thermophilusYS 48 I-1669 17 11 Streptococcus thermophilus YS 52 I-1670 0 0Streptococcus faecium SF 2 0 3 Streptococcus faecium SF 3 I-1671 27 0Streptococcus faecium SF 4 0 12 Lactobacillus acidophilus LA 3 0 0Lactobacillus acidophilus LA 10 0 0 Lactobacillus bulgaricus LB 1 I-16649 0 Lactobacillus bulgaricus LB 3 I-1665 20 12 Lactobacillus bulgaricusLB 7 I-1666 14 0 Lactobacillus bulgaricus LB 77 I-1667 20 0Bifidobacterium infantis Bi 2 80 15 Bifidobacterium infantis Bi 3 90 10Bifidobacterium infantis Bi 4 100 26 Bifidobacterium infantis Bi 6 0 100

These strains have been deposited with the CNCM, Collection Nationale deCultures de Microorganismes, Institut Pasteur, 28 rue du Dr Roux, 75724Paris Cedex 15, France, under the following accession numbers:

Streptococcus thermophilus YS 46 I-1668 Streptococcus thermophilus YS 48I-1669 Streptococcus thermophilus YS 52 I-1670 Streptococcus faecium SF3 I-1671 Lactobacillus bulgaricus LB 1 I-1664 Lactobacillus bulgaricusLB 3 I-1665 Lactobacillus bulgaricus LB 7 I-1666 Lactobacillusbulgaricus LB 77 I-1667

The following strains are on the contrary kept at the Centro RicercheSitia-Yomo S.p.A.,—strada per mercino 3-ZELO BUON PERSICO (MILAN)—ITALY,distinguished by the below-reported identifiers:

Streptococcus faecium SF 2 SF 2 Streptococcus faecium SF 4 SF 4Lactobacillus acidophilus LA 3 LA 3 Lactobacillus acidophilus LA 10 LA10 Bifidobacterium infantis Bi 2 Bi 2 Bifidobacterium infantis Bi 3 Bi 3Bifidobacterium infantis Bi 4 Bi 4 Bifidobacterium infantis Bi 6 Bi 6

These results demonstrate that the majority of the strains tested by ushave a low capability to deconjugate the bile acids and that there arestrains that do not deconjugate at all. This observation is surprisingin that it has not been known that the lactic acid bacteria deconjugatedthe biliary salts. Furthermore, it is evident that the enzymes of thestrains are selective for the specific bile acid bound on the sidechain. In this study, the clearest example is offered by theBifidobacterium infantis Bi 6. This strain is not able to deconjugatethe glycine-conjugated bile acid but is able to totally deconjugate thetaurine-conjugated bile acid. Some other strains (LB 1, LB 7, LB 77, andSF 3) are unable to deconjugate TCA but are able to deconjugate GCA to acertain extent.

To conclude, strains have been discovered that have a weak or zerocapability to deconjugate and dehydroxylate.

Example 2

Three healthy volunteers were tested for their content of bile acidsfollowing treatment with a lactobacilli preparation containing 1×10¹¹cells of Streptococcus thermophilus YS 52 per gram for a daily total of6 g for 28 days. Before beginning the treatment and after 12 hoursstarvation, the subjects were intubated and the gallbladder bile,following stimulation with ceruletide, was collected and frozen at −80°C. The gallbladder contraction was assessed by echography and theposition of the tube, in the second portion of the duodenum was checkedby Rx (fluoroscopy).

After a 4 week treatment, the subjects underwent a second intubation andcollection of bile. The bile samples were then tested for their contentof some bile acids as previously described. The results are shown inTable III.

TABLE III Patient #1 Patient #2 Patient #3 Bile Acid Before After BeforeAfter Before After Glychenodeoxycholic 32 15 22 15 28 12Glycodeoxycholic 6 5 9 2 4 3 Glycoursodeoxycholic 1 5 1 7 1 4Taurocholic 9 26 15 25 12 21 Taurodeoxycholic 1 3 5 8 3 9 NOTE: (thebile acids are listed following the hydrophilic capacity order, that isin inverse relation to detergency) Taurocholic TaurodeoxycholicGlycoursodeoxycholic Glycodeoxycholic Glychenodeoxycholic

This experiment is a confirmation of what is shown in Example No. 1,that is: a lower deconjugation in one of the primary bile acids ifbacteria being the object of the present invention are administered. Theachieved result is a longer maintenance of the primary bile acids in theenterohepatic circulation.

The properties of the bile acids are reported in the note to Table III.Thus, according to these results the administration of selected strainsof bacteria can reduce the detergency property and therefore thecytolytic activity of the bile acids.

Example 3

Fourteen patients with chronic hepatitis were treated with a bacterialpreparation containing Streptococcus thermophilus YS 46 and YS 48 (twostrains), and Lactobacillus bulgaricus LB 1, LB 7, and LB 77 (threestrains). Each strain had been brought to a concentration of 150×10⁹cells per gram before being mixed with the others, to prepare a mixturecontaining the same parts by weight of each strain. 6 grams per day ofsaid mixture were administered for 28 days. Liver enzymes were measuredbefore and after the treatment, and the results are shown in Table IV.

TABLE IV Influence of the Treatment with the Bacterial Mixture on LiverEnzymes Aspartate Transaminase (AST; SGOT) and alanine transaminase(ALT; SGPT) AST (SGOT) ALT (SGPT) Patient Before After Before After #192 59 102 46 #2 89 67 96 42 #3 174 86 97 39 #4 121 91 102 66 #5 116 81111 55 #6 156 87 94 76 #7 163 66 69 37 #8 78 64 122 57 #9 109 39 87 86#10 166 70 102 48 #11 56 24 118 62 #12 131 83 96 79 #13 137 86 94 74 #1484 87 144 114 Mean 119 71 102 63 Standard deviation 36 19 17 21Significance Student p < 0.001 p < 0.001 t test for paired data

Obviously, numerous modifications and variations of the presentinvention are possible in light of the above teachings. It is thereforeto be understood that, within the scope of the appended claims, theinvention may be practiced otherwise than as specifically describedherein.

1. A bacteria strain characterized by exhibiting: (a) a 7a-dehydroxylaseactivity of less than 50%, and (b) a bile acid deconjugation activity ofless than 50%, and descendants, mutants and derivatives thereofpreserving activities (a) and (b).
 2. The strain of claim 1, which is agram-positive bacteria strain.
 3. The strain of claim 1, belonging to aspecies selected from Streptococcus thermophilus, Streptococcus faecium,and Lactobacillus bulgaricus.
 4. The strain of claim 3, wherein thebacteria strain is Streptococcus thermophilus YS 52 deposited with theCNCM, Collection Nationale de Cultures de Microorganismes, InstitutPasteur, under the accession number 1-1670.
 5. The strain of claim 3,wherein the bacteria strain is Streptococcus thermophilus YS 46,deposited with the CNCM, Collection Nationale de Cultures deMicroorganismes, Institut Pasteur, under the accession number 1-1668. 6.The strain of claim 3, wherein the bacteria strain is Streptococcusthermophilus YS 48, deposited with the CNCM, Collection Nationale deCultures de Microorganismes, Institut Pasteur, under the accessionnumber 1-1669.
 7. The strain of claim 3, wherein the bacteria strain isStreptococcus faecium SF 3, deposited with the CNCM, CollectionNationale de Cultures de Microorganismes, Institut Pasteur, under theaccession number 1-1671.
 8. The strain of claim 3, wherein the bacteriastrain is Lactobacillus bulgaricus LB I deposited with the CNCM,Collection Nationale de Cultures de microorganismes, Institut Pasteur,under the accession number 1-1664.
 9. The strain of claim 3, wherein thebacteria strain is Lactobacillus bulgaricus LB 3 deposited with theCNCM, Collection Nationale de Cultures de Microorganismes, InstitutPasteur, under the accession number 1-1665.
 10. The strain of claim 3,wherein the bacteria strain is Lactobacillus bulgaricus LB 7 depositedwith the CNCM, Collection Nationale de Cultures de Microorganismes,Institut Pasteur, under the accession number 1-1666.
 11. The strain ofclaim 3, wherein the bacteria strain is Lactobacillus bulgaricus LB 77deposited with the CNCM, Collection Nationale de Cultures deMicroorganismes, Institut Pasteur, under the accession number 1-1667.12-36. (canceled)